Sean Butze

Many users do not compress or resize their images before uploading them into a post, and oftentimes WordPress’s maximum upload limit of 2MB-10MB is still too large to prevent the insertion of photos that can signficantly slow down a website.
WP Image Size Limit allows an administrator to set a custom file size limit that is specific to image files and smaller than WordPress’s general file size limit.
This is especially useful when you need to put tighter restriction on image uploads but want to preserve the ability to upload larger files of other formats (audio, video, etc.).

WP Image Size Limit

Just what I needed to tamp down those designers who think it's okay to use 20MB images!

Brilliant

Adds a new setting under Settings -> Media where an admin can set a maximum upload file size for image files.

Alexandre Froger

Ever wanted to make your media truely private? Make sure images, videos and other files are only accessible to chosen roles, or cannot be hotlinked, with permissions specifically set per item.
This plugin adds the following major features to WordPress:
<ul>
<li>Media Privacy: Lock access to items in the Media Library by preventing hotlinks only or by limiting access to files to selected user roles.</li>
<li>User-friendly forbidden handler: Images set to private do not break on the frontend. Instead, they are replaced by a simple access denied SVG picture – the forbidden handler can be replaced using the filter hooks <code>pvtmed_forbidden_response_content</code> (<code>apply_filters( 'pvtmed_forbidden_response_content', $forbidden_response_content, $file );</code>) and <code>pvtmed_forbidden_mimetype</code> (<code>apply_filters( 'pvtmed_forbidden_mimetype', 'image/svg+xml' );</code>).</li>
<li>Customizable for more granularity: Restricted media will be checked for autorization – plugin developers can hook into the <code>pvtmed_is_authorized</code> filter (<code>apply_filters( 'pvtmed_is_authorized', $authorized, $attachment_id );</code>) to apply more complex conditions for authorization.</li>
<li>Optimized private media delivery: Files with access restriction are served using streams without loading the file entirely in memory before delivery, and WordPress files are loaded as lightly as possible for an optimised server memory usage.</li>
<li>Fallbacks: Restricted files are kept in an alternate <code>wp-content/pvtmed-uploads</code> folder (or equivalent if <code>WP_CONTENT_DIR</code> is not the default) ; fallbacks are in place to make sure:
<ul>
<li>moving a media to private does not break previously embedded media (javascript dynamic fallback with notice on post edit screen – Classic Editor only). </li>
<li>deactivating the plugin does not break previously embedded media (database update). </li>
<li>deleting the plugin does not break previously embedded media (database update). </li>
</ul>
</li>
</ul>
A <a href="https://codex.wordpress.org/Must_Use_Plugins" rel="nofollow ugc">Must Use Plugin</a> <code>pvtmed-endpoint-optimizer.php</code> is installed automatically to make sure WordPress is loaded as lightly as possible when requesting restricted media items. Developers can safely edit it to enable their plugin to execute during such request if necessary.
The media privacy policy is set per media item – therefore, this plugin is not a replacement for general image hotlink prevention plugins, but is ideal for anyone looking for preventing direct links to files depending on specific conditions.

Private Media

Add access restrictions to specific items of the WordPress Media Library.

WP Image Size Limit vs Private Media